Mahasi Sayadaw has trained some of the world's best meditators- his knowledge of the commentaries and suttas are superlative. For all the armchair meditators and commentators to compare themselves with this level of understanding is not meaningful. See his comments on the 'progress of insight' below:
VII. Purification by Knowledge and Vision
15. Path Knowledge
It is followed immediately by knowledge that abides in that same Nibbana, which is void of formations since it is the cessation of them. This is called "path knowledge." It is also called "purification by knowledge and vision."
16. Fruition Knowledge
That again is immediately followed by knowledge that belongs to the final stage and continues in the course of its predecessor. It abides in that same Nibbana, which is void of formations since it is the cessation of them. This is called "fruition knowledge."
17. Knowledge of Reviewing
The duration of that threefold knowledge of maturity, path, and fruition is, however, not long. It is very short, and lasts for just an instant, like the duration of a single thought of noticing. Subsequently there arises "knowledge of reviewing." Through that knowledge of reviewing the meditator discerns that the insight leading to emergence came along with the very rapid function of noticing, and that immediately after the last phase of noticing, the path consciousness entered into the cessation (of formations). This is "knowledge reviewing the path."
He also discerns that the consciousness abided in that same state of cessation during the intervening period between the path and reviewing. This is "knowledge reviewing fruition."
He further discerns that the object just experienced is void of all formations. This is "knowledge reviewing Nibbana."
In this connection it is said in the Path of Purification: " 'By that path, indeed, I have come'; thus he reviews the path. 'That blessing was obtained'; thus he reviews the fruition. 'That state has been penetrated as an object by me'; thus he reviews the Deathless, Nibbana" (Visuddhimagga, xxii, 20).
Some meditators, but not all, have "reviewing of defilements."
After having reviewed in this way, the meditator still continues the practice of noticing bodily and mental processes as they become evident. But while he is thus engaged in noticing, the bodily and mental processes appear to him quite coarse, not subtle as before at the time of the knowledge of equanimity about formations. Why is this so? This is so because the knowledge present now has the nature of the knowledge of arising and passing away. For when the noble disciples (namely, stream-winners, etc.) resume the practice of insight (by noticing), the knowledge of arising and passing away usually arises at the beginning. This is the usual course of order in this respect.
However, when some meditators emerge from the attainment of path and fruition, great faith, happiness, rapture, and tranquillity, produced by virtue of the attainment, arise flooding the whole body. Owing to that, they are unable to carry out the practice of noticing anything apparent at that time. Even if they make double effort and attempt to proceed with the practice of insight, they fail to discern the phenomena clearly and separately, at the moment of their occurrence. They continue to experience only rapture, tranquillity, and happiness, which occur with great force. This state of mind, which is extraordinarily serene through the strong faith prevailing, lasts for one hour, two hours, or more, without break. Because of this, meditators feel as if they were in some such place as a wide open space suffused with radiance and most delightful. The rapture and happiness, of a serene character, that then arise are praised by meditators thus: "Surely, I have never before felt and experienced such happiness!" After two or three hours have passed, that faith, happiness, rapture, and tranquillity will fade. The meditators can once again proceed with noticing the bodily and mental processes as they occur, distinguishing them separately, and they will be able to discern them clearly. But at that time, too, first the knowledge of arising and passing away will appear.
18. Attainment of Fruition
While he is thus engaged in noticing, his insight knowledge will gradually grow, and soon will again reach the stage of equanimity about formations. If his power of concentration is still short of perfection, only the equanimity about formations will go on repeating itself. But if his concentration has reached perfection, then, in the case of one who does the insight practice of noticing with a view of attaining only to the first path and fruition, the fruition consciousness of the first path alone reaches cessation of formations by way of the attainment of fruition. This occurs in precisely the same way as the path and fruition consciousness that occurred earlier in the consciousness-sequence belonging to the initial attainment of the first path. The only difference here is the capacity of the fruition attainment to last long.
One should also set one's mind resolutely upon the further tasks: to be able to repeat the achievement of fruition attainment, to achieve it rapidly, and, at the time of achievement, to abide in it a long time, say for six, ten, fifteen or thirty minutes, or for an hour or more.
In one who applies himself to achieving the attainment of fruition, knowledge of arising and passing away will arise at the beginning. Advancing from there in the due sequence, soon the knowledge of equanimity about formations is reached. But when skill in the practice has been acquired, the knowledge of equanimity about formations will arise quickly even after four or five acts of noticing. If the power of concentration has reached perfection, the fruition consciousness will repeatedly become absorbed in cessation by way of fruition attainment. The mind can thus reach absorption even while one is walking up and down, or while taking a meal, and the fruition attainment can remain for any length of time resolved upon. During the fruition attainment, the mind will abide only in the cessation of formations and will not be aware of anything else.
Sutta should be understood in the light of practice. Practice should be understood in the light of sutta. Otherwise having only sutamaya panna is incomplete. Bhavanamaya panna is essential.